Investigation of soda-lime glass viscoelasticity under a 1064 nm laser with photoelasticity

Understanding the thermo-mechanical interactions in laser-processed glass microstructures is essential for suppressing defect formation, modulating stress fields, and engineering precision micro-architectures. This study combines photoelastic stress measurements with viscoelastic modeling (Generalized Maxwell model) to analyze 1064 nm laser effects, validated by post-cooling microscopy. Key discoveries reveal that glass transition temperature ( T g ) triggers molecular rearrangement, scrambling principal stress directions and reducing stress differences. Central stress depletion accompanies expanding thermal gradients, while edge stress rotation (radial→circumferential) creates ring-shaped protrusion featuring a flattened central region and a wrinkled periphery. Over irradiation, initial protrusion growth transitions to viscous smoothing, with stabilized geometries showing progressive lateral spread and post-process height reduction. Stress-morphology correlations advance precision laser processing strategies for glass microfabrication.